Here’s what a typical 100 Amp Zinsco panel looks like:
Our Zinsco electrical panel that was on our Eichler REALLY needed replacing. There were actual black char marks around the panel (which is evidence of arcing) and there was a significant leak directly above the panel. Most electricians will say that a 1953 Zinsco panel is faulty by design (link here). In my opinion I think there are two main problems:
1). The breakers are VERY old and old breakers tend to get stuck or locked in place (a locked breaker that does not trip can arc or cause a fire from excess heat).
2). The design has aluminum bars (where the breakers attach) that can oxidize over time.
Also, I do not think the box was water tight but I can’t be sure.
So, here’s what our electrician did:
1). First, he pulled a permit from the county (we do not live within city limits so we only needed one permit).
2). Next, he ordered the panel, grounding rods, and heavy gauge copper grounding wire. (the grounding rods are large 6 ft. copper rods).
3). With the permit displayed he setup a time for PG&E to shut off the power. Their availability wasn’t too great so we had to wait an extra 2 weeks.
4). With the power off he re-framed a small portion of the house where the old panel was. Oh, did I mention that a corner of the house was rotted from a leaky roof? Anyway, the new framing made the new box fit correctly.
5). He also “bonded” the gas line to the water line to the grounding rods. This guarantees that all the piping is grounded in the home. As an extra safety measure he put in two grounding rods (now a code requirement).
6). After sitting in the dark until almost 1am PG&E came out and turned the power on (bad PG&E!!)
For reference, the panel is a “Square D” 200 Amp Outside Surface Mount Panel.